Train-control system



May 14, 1929- f T. E.. CLARK ET AL Y 1,712788 I TRAIN connor. SYSTEM v Filed Jungla, 1925 '2 sheets-sheep 1 Y A' Q f5 Q A TTORNE Y.

May 14, '1929- T. E.' CLARK dEr Aj.' 1,712,788 TRAIN CONTROL SYSTEM Y I 2 Sheets-Sheet 2 Filed Jne 12. 1925 A TTORNE Y.

IN VEN TOR.

Patented May 14, 1929.

`,UNITED STATES PATENT OFFICE.

THOMAS E. CLARK AND JAMES E. CLARK, OFDETROIT, MICHIGAN, ASSIGNORS TO CONTINUOUS TRAIN CONTROL CORPORATION, OF DETROIT, MICHIGAN, A COR- PORATION OF MICHIGAN.

TRAIN-CONTROL SYSTEM.

Application filed .Tune 12, 19215. Serial No. 36,628.

provide a system oi2 this character whereby one of two audible signals is caused to sound in the locomotive cab whenever the locomotive passes over a` track section 1n which a current is propagated, the signal depending upon the wave length ot the current in the track and the current being ot one wave r length when the nent or second track section in advance is occupied and of another wave length when the three blocks in advance are unoccupied.

The train control system hereinafter described is shown in the drawings associated with a signal system ot the three lamp appreach light type connected to rails divided into blocks, but it is to be understood that our invention is not limited to use in Connection with a signal system of this character but may be used with any desired type of signal system or may be used without signal lamps.

This invention consists in a system ot' control stations each enlbodying an` electron or vacuum tube containing a iilament which receives a current of' aboutten volts, Whichtube y is connected in an oscillating circuit `containing fixed and variable condensers and 1nduction coils and means to modify the cir-` cuit so that it will transmit currents of two different wave lengths to the track, one whenA the track section either the neXt or the second in advance is occupied and another when the next three sections or `blocks in advance are unoccupied, and in connection with such taclowayv stations, it comprises an installation upon a locomotive for picking up magnetic lines of torce corresponding to said and adapted to select the circuit between a' battery and one or the other of said audible signals according to the pickedaip current.

'It also consists in a normally closed cir cuit between a current source and an electropneumatic valve connected into the air brake system of the vehicle, which circuit is opened when a predetermined one oi the said currents is picked up, and a pair of forestalling keys, which, when both are depressed, provide a new energizing circuit for said electromagnetic `valve and thereby prevent the ap* plication of the brakes.

It further consists of the details of construction illustrated in the accompanying drawings and particularly pointed out in the claims.

In the drawings, F ig. l is a diagram of an installation mounted on a locomotive, the brake mechanism being shown in section. Fig. 2 is a diagram of a transmitting trans former, Fig. 3 shows three diagrams of track stations embodying both signal and control installations. j

Similar reference characters refer to like parts throughout theseveral views.

The signal installations, with which our novel control installations are combined, em-

body lamp stands provided with three signal lamps, preferably green, yellow7 and red, which indicate how the track in advance is occupied, the green lamp showing that the two blocks in advance are unoccupied, at which time the parts of the station are said to be in clear position; the yellow lamp showing that the second block in advance is occupied at which time the parts of the station are said to be in"caution position; and

the red lamp showing that the next block in advance is occupied, at which time the parts of the station are said to be indanger position. The lamps are respectively termed clear, caution7 and danger lamps. The track illustrated is that of one of two parallel tracks, each olf which is set apart for traftic in one direction which is considered to be from right to left in Fig. 3. The blocks and the stations therefor are lettered from A to D inclusive, and block A is supposed to be occupied. F or this reason, the parts of station B are in danger position, those of block C `in caution position, and those of block in clear position.

are shown in the i.

, provided with one or more armatures designatedby small letters, andin lthe, following description, t-he aimatures will be' designated by their respective letters following 'of the the numeral designating the relay to which they belong. Where the procedure is of advantage,a part of a station installation may be further designated by using the letter of its bloc-k o r station together with the numeral art.

` The ails 1 and 2 are'divided into blocks lby insulations 3 in the usual manner and adjacent the exit end ofeach block is a lamp stand a provided with red,` yellow and green lamps. Adjacent each station and in part controlling'it is a track relay 7 connected to the rails 'b wires 5 and 6. These relays are energized y track batteries 8 which connect to the railsby kmeansot wires v9 and 10, re-

sistances 11 Ybeing used to prevent damage Vto the vbatteries when the rails are short cir- KVcuited by means'of the axles of rolling stock.

AtA each station is a signal batteryA 12 'which con'nects to its lamp stand by a coinmon Wire 13. "The return circuitsfrom the lampsare controlled by a polar-neutral relay v14whichisenergized by current from the Abattery of .the neXt station ahead coming in over 'wire 15. When no current comes over wire V15,"relay '14y is' cle-energized and its Y armature@ remains in itslastposition, for

' y example, at its left .hand posit-ion, in block Y B. If positive current comes over this wire,

armature 14d swings clockwise, as at block D. If negativel current comes over the wire,`

theA armature swingsl counter-clockwise, as at block C. No rcurrent passes to the signal lamps 'when relay 7 is energized and this re- Y f lay remains energizedA until its block of track is occupied as will hereafter be explained. This results in great saving of battery cur- A rent for there is rno current used for the signal lamps at'any'station unless the bloclrto whichit is ,connected is occupied.

Referring now to Fig. 3, no current flows gized relay 7. As block B is unoccupied, no

,current flowsV tothe lampstand,'at B as all the'circiiits from the lamps are opened by,l the relayY 7, but if it were occupied andrelay 7 deL-energized, current would vflow over common wire 13 `to red lamp R and then over wire 17, armature 14, wire 20, armature 7a and wire 21 to thehbattery. lThe red lamp indicates danger in the blockl ahead, that is, that such block is occupied.

As block B is unoccupiedbut block A is occupied, negative current flows to relay 14C over wire 21, armature 14b and v15B and back from relay 14C over wires 16 and 25, armature 7,V wire 26, armature 14 and wire 13 to the battery. As block C is unoccupied, no current flows to the lamps at Cl, but if it were occupied, current would flow from the battery over common wire 13 to yellow lamp Y, then back over wire 18, armature 1t", wire 22, relay 14C, wire 20, armature 7'1 and wire 21 to the battery. The yellow lamp indicates caution in the block ahead, that is, that the second block ahead is occupied.

As blocks B and C are unoccupied, positive current flows over wire 13, armature 14." and wire 15C to relay 14D and back over wires 16 and 25, armature 7, wire 2G, armature 14a and wire 21 back to the negative end of the battery, and as block D is occupied, eurrent flows from battery 12 over connnon wire 13 to green lamp G at D, thence back over wire 19, armature 14d, wire 22, arma- "ture 14, wire 20, armature 7 and wire 21 to the battery.

The green lamp indicates ,clear in the block ahead, that is, that Y neither the next nor the second block in udvance is occupied.

In this figure, the circle 24 indicates the transmission device for propagatinfr highfrequency oscillating currents of different wave lengths in the rails. Current is conducted to this device by means ot the wire 63 which connects to the wire 13 and returns over the wire 64 connected to the wire 20. It is therefore evident that no current flows to the transmitter unless the relay 7 is deenergized, that is, unless the block to which the transmitter is connected is occupied. This again makes for saving of battery eurrent.

The current m11 emitter.

As indicated in Fig. 3, the wires 63 and (it connect to a motor-generator 65 and to the filament 66 of a vacuum or audion tube 67, an adjustable resistance 68 being provided in the lilainent circuit to control the temperature of the filament. The wire 63 is also the conductor of the high voltage from one side of the motor-generator 65 to the grid coil 80, and the wire 73 from thc other side of the motor-generator connects to the plate coil 74 ywhich connects to the plate 75 by means of wire 76.A This coil is shunted by the variable condenser 77 whereby the oscillations may be limited to a predetermined wave len vth and these oscillations are transmitted to t ie rails 1 and 2 by means of the wires 78 and 79 from the loading coil 81, t-he wires 78 and 79 preferably connecting to t-he wires 5 and 6. These oscillations are those which are transmitted when the second block in advance is occupied, that is,are of the danger wave length. A condenser 82 is shown connected into the wire 78 to exclude the direct current of battery 8 connected to the same block with the transmitter.

The polar-neutral relay'83 is energized `by current received from the second station in advance over wire 84, and the neutral armature 83a (Fig. 2) connects the Wire 85, which shunts the plate coil 74, to the polar armature 83h which is swung; clockwise by a positive current over Wire 84, under which condition the additional condenser 86 and Wire 88 are brought into the circuit,and is swung counterclockwise by a negative current over this Wire, when the second condenser 87 and Wire 89 are brought into this shunt circuit.` The shunt circuit embodying the condenser 86 so influences this c urrent transmitter thatclear7 Wave lengths are propagated in the rails, and the circuit embodying' the condenser' 87 causes oscillations of a third wave length, and While this particular current is not used to influence iiistininentalities on the locomotives, its production prevents the propagation ol danger77 current in the rails. For convenience, this current will be termed the caution current.

Referring new to station. B, no control current passes to the rails because block B is not occupied and relay 7 is energized. But it were occupied, current would pass over wires 13 and 63 to transmitter' 24 and over Wires (i4 and 20, armature 7LL and Wire 21 tothe battery. No current passes to the rear over the Wire 84A from the station of blech A as block A. is occupied and the circuit to this wire is opened by armature 7" of station A, so the relay 83E is do--cnergiZ-ed and the shortcircuit Wire 7 G carries all the current troni the plate coil 74, resulting' in the current of the shortest or danger Wave length being propagated in the rails. f

Connected to the wire 79, extending from the transmitter' 24 to the rails, is a relay 90 which responds to these hi,{.;'h-trequency currents, and attracts its armature a, closing a circuit to the slow-release relay 92,sa`id circuit consisting; ot the Wire 93, armature 90, Wirev 94, relay 92 and Wire 95 to `Wire G3. The energiaed relay 92 attracts its armatures. As soon as the assumed train '1" leaves block B, relay 9() becomes cle-energized, but relay"7 becomes energized, and acircuit to relay 92 over Wires 13, 63 and 95 to the relay and Wire 94, arn'iatlufe ULF", wire 96, armature 7 and Wire 21 to the battery is closed, and it reinains closed until its block is again occupied, when the lirst described circuit to this relay is again closed.

As stated betore, no current passesto relay 14B because block A is occupied. No current passes to lamp R of station B because block B is not occupied. No current passes to transinitter 24 of station B because this block is not occupied. Current passes from the negative end ot battery 12]B over Wire 21, armature 14., wire 15B to relay 14 oit station C, then over wires 16, 25, armature 7c, Wire 26, armature 14"L and Wire 13 to the battery. This current causes the armature 14(l ot' station C to swing countereloclrwise and positivo current to flow i from the battery 12 of station Corerwire 13,

mature 14 and wire 21 to the battery. This result in arn'niture 14(l ot station D swinging' clockwise.

It block B were occupied `and relay 7 there of de-energized, current would How to trans- 1nitter24 and oscillating current would be propagated in the rails of that block. But no current would be received over wirel 84A by the relay 83B because block A is occupied and its relay 7 cle-energized, so that armature Would not be attracted and the current transmitted would be oit the short Wave length to indicate danger. The distance troni the connecting points of wires 5 and G at which a locomotive picks up current will be dependent upon the vacuum tube G7, but the distance and the time dining which the locomotive occupies this energized track are sutiicient for the current to affect the instrumenw talities on the locomotive before the end of the block is reached.

Current to control relay S3 of block D flows troni battery 12 oit station B over Wire 13, ar-

`mature 14u, wire 26, armature 7, wires 25D,

16 and 28C, armature 7b of station C, Wire 30C, armature 92h, Wire 84C to relay 83D then over `wire 29D, armature 7", Wires 28D, 1G, and 15E,

armature 14') and wire 21 to the battery, caus-` ing arniature S3 of station D to be attracted to close the circuit to wire S5, and armature i 83 to swing counter-cloclnvisc to prevent the production ot the danger Wave length.

lt will be noticed that the current Hows to relay 88D over wire 84C and baclcovcr Wire 16. Il block A Were unoccupied, relay 14 would be energized and current from battery 12B would flow over wire 13, armature 14, wires 15, 16 and 2S to armature 7 et station D,

VWire 29 to relay 83 and thence over wire 84C, `armature 92, Wire 30, arma-ture 7", wires 2S,

1G and 25, armature 7C ot station B, wire 2G, armature 1.4d and Wire 21 to the battery. This would cause armature 83" of' station D to swing clockwise, as shown in Fir' 2, result ing in oscillating;` current of predetermined Wave length, differing troni the cilann'er current and the caution currei'lt, and designated as clear current hereinafter.

lt Vwill therefore be seen that when block A is occupied, and a train al'iproaches 'troni the right, a green lamp will be visible at the exit end of block lll (not shown) and the track et block E (not shown) will receive clear7 control current. When the train occupies block D, a green larnp will again be Visible at the exit end thereof and another or caution current will be in'opagrated in the rails of that block near the exit end thereof. When the train enters block C, a yellow light becomes visible at the exit end thereoitl and danger7 current is propagated in the rails vrent is. propagated in the at the Vexit end thereof. When the train enters blockv B, a red light becomes visible at the exit end ofthe block'and danger eurexit end'of this block also. y

Should any transmitting mechanism fail to function, its relay 90 will not be energized,

, nor will the relay 92 so that the circuits which embody the wire 84 of that station will be opened, resulting in danger current being propagated by the second station in the rear if its block is occupied. When relay 14 of any st ation fails to receive current, the next sta- Ation in the rear propagatesdanger current Thelooompotre installation. Mounted on the locomotive at an oblique kangle yto the rails and just in front of the leading axle ofthe locomotive Where the lines of magnetic flux are strongest, are two collector coils 98 and 100, the former connected to the thermo-junction heater current converter 99 and the latter to the converter 101. These converters may be of any desired type, and

the circuits of these coils are tuned respecv tively to resonance with the clear and danl 35 ger Acurrents propagated in the rails, by the adjustable condensers 102 and 103 respec' tively. The converters rectifythe picked up current or flux and may loe adjusted as desired, but in the present case it will be assumed that the coil 98 picks up magnetic flux created by the clear current in the rails and the coil 100 the iux created by the danger current. It is also assumed that the currents s are so rectiied that the relay 105 is energized by these rectified currents vpassing to it over wires 106`and v1,07 and that clear current in the rails causes the armature 105a to swing clockwise, and danger current causes this armature to swing in the oppositedirection. No provision is made to detect the third or f caution current.

lVhen clear,cu1rent causes the armature 105 to swing clockwise, current flows from thebattery109 overwire 110 and resistance 111,*armature 10o, wire 112, solenoid 113,

*wires 114, 115vand 116 to the battery. This energizes this solenoid and causes it to lift the valve 118 so that air under pressure may flow from the ordinary storage tank of Athe Vair brake system through pipes 119 and 120 to the whistle 121 which will continue to Y sound so long and as often as relay 105 receives current, which occurs while the l0eomotive isk travelingv through each length of track carry1ng.clear" current. The signal `oftraek which carries sufficient. control current to cause the locomotive installations to operate are less than the lengths of the block, the whistle 121 will sound at intervals only and so notify the engine crew that the locomotive is leaving the clear block.

The armature 105EL is normally in neutral posit-ion as shown, and current normally passes from the battery over wire 110 and resistance 120, armature 108, wires 121 and 124 to relay 108 and over wires 125, 120, 127 and 116 to the battery, normally energizing this relay which attracts its arumtures 108" and 108", the former closing its stick circuit and the other closing the circuit from wire 110, armature 108",Y wire 128, solenoid 117, and wires 1.15 and 116 to the battery. T his energizes the solenoid 117 which causes the valve 129 to close the passage between the pipes 119 and 138. The resistance of 111 and 120 may be equal but each is higher than the resistance of relay 108.

lVhen armature 105 swings counter-eloekwise as explained above, relay 108 is short circuited, and the current flows from wire 110 over resistance 111, armature 105, wires 101, 126, 1.27 and 116 to the battery, the resistance o1 111 being less than that of relay 108 and resistance 120eombined. Thisrelay being short circuited, it drops its armatures and opens the circuit to solenoid 11.7, which releases the valve 129 and air fiows from the pipe 119 to pipe 138, resulting in the sounding of whistle 139 and normally in the application of the brakes. This valve and its solenoid is usually termed an electro-pneumatic valve in this art.

Two forestalling keys 122 and 123 are provided so that as soon as the whistle 139 sounds, they may be depressed simultaneously by the engineer and fireman, to close an auxiliary circuit to relay 108 over wires 110, and 161, key 123, wire 162, key 122, wires 103 and 124, which will supply current to this relay as soon as armature 105" swings eounterelockwise. But these keys must be depressed simultaneously and an accidental closingr of one of them has no effect. As the relay 105 is energized only during the short time the eolleetor coils 98 and 100 are passing along charged rail sections, the time duringr which the valve 129 is open is not suieient to cause the application of the brakes, provided the engineer and fireman are both alert and depress their keys. As soon as solenoid 117 isenergized and valve 129 is closed, the

danger whistle ceases to sound.

When the solenoid 117 is de-energized` air flows through the pipe 138 to the whistle 139 and to the cheek-valve body 140, lifting the valve 142 and passing through pipes 143, 144 and 145 to the control cylinders 146 and 147 and to the storage tank 148, which merely accumulates air and permits of delayed 1nove ments of the pistons 149 and 150.

The piston 149 moves the valve 152 to close the normal passage between the train pipe 130 mid the train valve 131 so that the engineer' cannot supply `air to the train pipe to prevent the setting oi' the brakes. But he can set his valve to exhaust the train line pipe. The check valve 1525 will permit this upward flow ot airli i lhen thcvalve S is forced to its innermost position, it connects the small passage 5l- (Which is controlled by the needle valve and is connected to the outside air by the vent 156) to the space above the piston 157. lli/'hen the parts are as shown in Fig. 1, the air pressure on both sides of this piston 157 is the same, and the passage 1541 is cutoff from the space above the piston 157 by the valve 158 connected to the piston 150. But when the valve 158 permits the air above the piston 157 to escape through the vent 1:36, the pressure below this piston, being lull train pipe pressure, Will lift this piston and with it the valve 159, permitting the escape ci" air 'from the train pipe through the restricteiil vent 1GO, Which results in setting the brakes. rlhis How will be sloiv because of the tank 13st which holds air at the saine initial pressure and which must also es ape tllrough the vent 156.

All this time the Whistle 139 is sounding.

and it the engineer and fireman are both alert, each can operate his orestalling key to cause th e electro-pneumatic valve to close. llut unless the iforestalling keys are depressed, air Will continue to escape from the train pipe and resultin the brakes being applied. l llilhen the control keys are depressed and the solenoid 1lienergized to stop the flow oil air ifrom the pipe 119, the engineer may open his train valve 131 to permit lull pressure air to 'flow into the train pipe Which will result in the valve 1512 and piston llbeing pushed Vback to normal position, which is rendered possible by the escape ot the air in thc pipes 1413, 141-4 and 1115, cylinders 146 and ist? and tank 11-.8 through the Whistle 139, the valve 1112 being so formed as to permit a slow flow ol' air to the pipe 138. The new pressure in the train pipe 130 and its branch 132 also forces the valve 158 and piston 150 back to the position shown in Fig.

l/Vhenever therefore, the collector coil 100 passes along a properly energized zone Where it picks up current of the proper Wave length, the relay 105 will cause the Valve 129 to adinit high pressure air to the cylinders 146 and la7, which results in the application of the brakes unless i'iorestalled by the proper use oit the keys 122 and 123 which should be so placed that they cannot be operated by one man.

The details of construction and the ar rangements and positions of the various parts may all be changed by those skilled inthe art Without departing from the spirit olf our in vention as set *forth in the following claims.

lr-Veclaim 1. In train control system, a tracli. di vided into blocks, a train control station connected to the rails olf each block and each embodying a current source and means 'for propagating high-:lrequency `currents of dill'erent wavelengths in the rails oi' the block 'to Which itis connected, and means embodying conductors extending continuously from a control stationto the current source of the second block in advance to determine the Wave lengths of such currents.

In a train control system, a track diH vided into blocks, signalv and control installations connected to the rails at the enit end oit each block,` each signal installation embodying a current source and a group oi electric signal. lamps, said control installation enibodying means 'for propagating high-frequency currents of' dillereut wavelengths in therails of its block, means influenced by a vehicle in a block for causing the operation ot the signal and control installations oit that block, and means energized by the current source at the second installations in advance todetermine the wavelength ot the propagated current.

3. In a train control system, a tracli divided into blocks, signal and control installations connected to therails at the enit en d oit each block, each signal installation our bodying a current source and a group oi electric signal lamps, said control installation embodying means for propagating ln'gh-irequcncy currents oit diii'erent wave-lengths in the rails oli its block, means influenced by a vehicle in a blocl; for causing the operation of the signal and control installations of that bloclr,` and means energized by the currciit source at the .second installations in advance to determine the wave-length oil the propagated current, and means energized by the current source at the nent installations in ad- Vance to determine the signal lamp to receive current.

l. In a train control system, a traclt divided into blocks, a train control station connected to the rails of each block and einbody ing a current source and means for propagating high-frequency currents of diilcrcnt Wave-lengths in the rails oli each block, a polar relay to determine the Wave-lengths of said currents, conductors connecting said relay to the current source of the second sta tion in advance, and means at said second station todetermine the direction of current passing' to said relay.

5. In a train control system, a track divided into blocks, a signal and train control station connected to the rails olE each block and embodying a current source, means for propa- 30 Y named polar relay to the current source of l. gating high-frequency currentsof different j Wave-lengths in the rails of each block, and

relay, conductors connecting said` second named polar-relay to the current source of the next station in advance, and means at said next station toV determine the signal lamp to receive current.

6.` In a train control system, a track divided into blocks, a signal and train control sta- Ation connected to the rails of eachblock and embodying a current source, means for prop* agating high-frequency currents of diferent Wave-lengths in the rails of each block, and a group of electric signal lamps, a polar relay toy determine the Wave-lengths of said currents, a second polar relay to determine the signallamp to receivecurrent, conductors connectingsaid first named polar relay to the current source of the Asecond station in advance, means at said second station to determine the direction of current passing to said relay, conductors connecting said second the next station Vvin advance, and means at said next station to determine the 'signal lamp to receive current, and means influenced by a Vehiclerin a block to cause the functioning of the propagating means and of the selected lamp.

7. In a train control system, a track divided into blocks a train control station connected to the rails of each block and embodying a current source and means for propagating higlrfrequency currents of diiferent wavelengths in the rails of each block, a polar relay to deterlnine the Wave-lengths of said cnrrents, conductors connecting said relay to the current source of the second station in advance, and means at said second station to determine the direction of current passiiw to each relay, and means controlled by the luglifrequency current propagating mechanism of the next station in advance to open and close the circuit to said polar relay.

8.l In a train control system, a track divided into blocks` a train control station connected to the rails of each block and embodying a current source and means for propagating highfrequency currents of different wavelengths in the rails of each block, a )olar relay to determine the wave-lengths o said currents, conductors connecting said relay to the current source of the second station in advance, and means at said second station to determine the direction of current passing to said relay, a current source and a relay connected to the rails of each block at opposite ends thereof, and an armature of said relay for closing the circuit between the current source and the current propagating means.

THOMAS E. CLARK. JAMES E. CLARK. 

